var box = [];
var $container = $("#container");

/** DragBox Init */

function DragBox(url, controller) {
this.url = url;
this.htmlcontent = "";
this.controller = controller;
this.test = "null";

this.requestContent = function() {
    $.get(this.url, null, function(res) {
        $container.append(res);
    });
}

this.requestContent();
$(this).attr("id", this.controller);
$("#" + this.controller).hide().fadeIn(1000).draggable();
}

var links = $("li a");
for(var i = 0; i < links.length; i++) {
links[i].onclick = function() {
    box.push(new DragBox($(this).attr("href"), $(this).attr("controller")));
    return false;
}
}

function DragBox(url) {
  // init stuff...

  this.requestContent = function(callback) {
    $.get(url, function(res) {
      var $element = $(res);
      $element.appendTo($container);
      $element.hide();
      // The job is done, execute the code inside callback
      callback($element);
    });
  }

  // Render the requested html content and make it draggable
  this.requestContent(function($element) {
    $element.fadeIn(1000).draggable();
  });

}

$(document).on('click', 'li a', function(e) {
    if ( /* some condition */ ) {
        var some_var = new DragBox(params);
    }
});